And now, dear readers, we bring a bit of closure to the “infamous” EYAWTKALSBWATA series…having previously covered grain windows and rod actions in Part 1, personal casting mechanics in Part 2, and fishing conditions and payloads in Part 3, we’d like to shed a little light on what might be a confusing aspect of line selection: length to weight ratio. As a bonus, we’ll also attempt to bring some clarity the $64 question: How hard (or easy) do you wanna make your fishing / casting experience?

In Part 3, we established a general axiom about line weights and fishing conditions, namely, if you are fishing small flies near the surface, you opt for a line on the lighter end of your rod’s grain window, and for sink tips and big flies, you use a line on the heavier end of the grain window. While this is true for lines in the 23’ to about 40’ range, it becomes less true on either side of those lengths…why?


Instead of looking at overall grain weight for the answer to this conundrum, we’ll focus instead on the length-to-weight relationship of the line and express that as “Grains per Foot”, or GPF. Simply put, GPF is a measure of the averaged grain weight of a foot-long section of any particular line. For the sake of demonstration, let’s use the ECHO E3 6127 (our favorite rod!) to establish a “real-world” scenario by which we can flesh out the GPF story.

The stated grain window of the E3 6127 is 390 to 480 grains, so if we are choosing a line for sink tips and sustained-anchor casting we would anticipate using a line in the upper end of that window, say, 450 to 480 grains. The AirFlo Skagit G2 in 450 or 480 grains is a great match for the 6127, but if you want to use a shorter line, the AirFlo Skagit Scout in 420 or even 390 grains is a good choice, and this is where GPF comes into play. The Skagit G2 in 480 grains has a GPF of almost 21 (480gr / 23’ = 20.87GPF), and the Skagit Scout in 420 grains, while an overall lighter line, has a GPF of 24 (420gr / 17.5’ = 24GPF). When compared to the G2, the Scout has more mass per foot, and that means you can use a shorter, lighter line and still achieve the same result.

Sticking with the 6127, if you wish to choose a line for touch-and-go casting and/or light flies and shallow presentations, you would probably choose a line in the lower end of the grain window, something around 390 to 420 grains. The AirFlo Scandi Compact in 420 grains is an awesome line on the E3 6127, but if you want to throw a longer line, the AirFlo Delta Spey II in 460gr is a good place to start. Once again, this is a function of GPF, with the Scandi having a GPF of just over 13 (420gr / 32’ = 13.125GPF) and the Delta having a GPF of 10 (460gr / 46’ = 10GPF). So in this case the Delta, while heavier than the Scandi, has less mass per foot, and this means that you can use a longer, slightly heavier line and not overload the rod.

So – on to the $64 question…How hard (or easy) do you wanna make your fishing / casting experience, and what role does that play in line selection? As it turns out, line selection can play a big role in your enjoyment of casting and fishing, so here are a few things to consider:

Average cast length – If you are fishing a small river or a narrow, nearshore section of a large river where you don’t have to cast far, a shorter line is often the best tool for the job. By the same token, a longer line is better when fishing a broad tailout or a wider piece of holding water. There are tradeoffs to each – longer lines can be more difficult to cast in the wind and can be harder to control during the swing, but you don’t have to strip in running line like you do with a shorter head, and while you CAN shoot great distances with shorter heads, the longer lines make it easier with a little bit of practice.

Wading depth – The deeper you wade, the less distance there is from the water to the tip of the rod. The less distance from the water to the tip of the rod, the more precise and controlled your D-loop formation needs to be – simply put, the deeper you wade, the harder it is to cast a longer line.

Clearance room – Wouldn’t it be perfect if every fishy run had a wide gravel bar with no bushes to snag with your D-loop? Unfortunately, it seems like the fishiest water has the nastiest obstacles to make your casting a disaster…in areas with limited room behind you for D-loop formation, shorter lines excel.

Ease of use – Generally speaking, shorter lines are easier to cast and require less precision in timing and technique than longer lines, but the tradeoff is stripping and managing a lot of running line for a shorter head.


As we have seen over the range of this series, line selection can seem like a daunting task. Never fear, because Uncle Tim and the fine folks at ECHO have put together a handy Cheat-Sheet of line recommendations for every rod in their lineup. Armed with the Cheat-Sheet and a few considerations on your own personal style and fishing conditions, you’ll be casting all the way to the fish in style and comfort in no time flat.

As always, feel free to join the conversation with a comment, critique or your own experiences!

Echo/Airflo Pro Ambassador Mark Hieronymus is a senior guide for Bear Creek Outfitters, pattern designer for Umpqua Feather Merchants, and serves as the Trout Unlimited Southeast Alaska Sportfish Outreach Coordinator working to protect native spawning grounds in the Tongass National Forest. No bones about it…Mark’s one busy dude.

Featured shot: ECHO Ambassador Harookz; Body shots: D Bone